at 1:47 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Thu, Aug 23, 2018 at 02:39:59PM +0100, Will Deacon wrote: >> The only problem with this approach is that we've lost track of the granule >> size by the point we get to the tlb_flush(), so we can't adjust the stride of >> the TLB invalidations for huge mappings, which actually works nicely in the >> synchronous case (e.g. we perform a single invalidation for a 2MB mapping, >> rather than iterating over it at a 4k granule). >> >> One thing we could do is switch to synchronous mode if we detect a change in >> granule (i.e. treat it like a batch failure). > > We could use tlb_start_vma() to track that, I think. Shouldn't be too > hard. Somewhat unrelated, but I use this opportunity that TLB got your attention for something that bothers me for some time. clear_fixmap(), which is used in various places (e.g., text_poke()), ends up in doing only a local TLB flush (in __set_pte_vaddr()). Is that sufficient?
